.50 Browning Armour Piercing Incendiary & explosive
API Mark Iz
Several armour piercing incendiary bullets were designed during WW2, including DD/SAA/203, D6/L/1216, DD/L/1257 and D6/L/902 which became the Mark 1z.
"Cartridge S.A. Armour Piercing Incendiary .50 Browning Mark 1z" was approved to design D6/L/902 in 1944 (the design drawing is first dated February 1944) and was essentially a copy of the American M8 API.
The case was a standard British made .50 Browning with a Berdan primer. In theory the primer annulus should be green but examples seen have all been purple. The headstamp included the Mark number and was typically "K 56 .50 IZ"
The boat tailed bullet had a gilding metal envelope with a hardened steel core without a lead sleeve. The tip was filled with12 grains of SR 365 incendiary composition and there was a lead base plug. The bullet had a silver tip for identification and weighed 660 grains.
Muzzle velocity was 2,850 fps at a pressure of between 23.2 and 24.2 tsi.
Explosive
There were a number of designs of explosive and explosive incendiary bullets produced during WW2 but none were adopted for service.
Like the AP shot, they had steel bodies with a copper base cup to take the rifling. The bodies were hollowed to take the explosive filling and threaded for a nose fuze which could be either plastic, steel or brass. By June 1944 the decision had been taken to discontinue development of plastic fuzes.
The designs were:
DD/L/14088A This could be fitted with either a brass or plastic fuze and the filling was contained in a gilding metal cylinder.
DD/SAA/162 This was fitted with a brass fuze and filled with TNT/SR 365 mixture.
DD/SAA/168 This could be fitted with either a brass, plastic or steel fuze.
The filings tested were:
TNT/aluminium
CE/aluminium
TNT/SR 365
CE/SR 379
Above: .50 Browning explosive believed to be design DD/SAA/162
DD/SAA/162 with fuze removed. Various HE and HE/I bullets, designs unknown.
Post war, Kynoch developed a number of HE and HE/I designs in the 1950s. These were made with thick brass or gilding metal bodies with brass nose fuzes. They were unusual in that they were designed to contain a liquid explosive filling.
A variety of fuzes was developed, varying in the filling and the arrangement of the gaines and detonators. One design was MTS 2755 but little else is known about them. The Ministry of Defence may not have been the customer.
Sectioned examples of Kynoch HE bodies.